Zimbabwe Prime Minister Morgan Tsvangirai said Thursday he will contest President Robert Mugabe's "unilateral and unconstitutional" decision to call for a general election on July 31.

"President Mugabe's actions are a unilateral and flagrant breach of our constitution. I, as Prime Minister, cannot and will not accept this," Tsvangirai told journalists in Harare.

Zimbabwe's highest court last month ordered Mugabe to ensure that the country holds elections by the end of July.

The elections -- to be held under a new constitution endorsed in a referendum in March -- will end the power-sharing government of Mugabe and Tsvangirai formed in 2009. That followed a violence-marred election in 2008 in which Mugabe had claimed victory but regional leaders regarded as a sham.